The present invention relates generally to a method for efficiently and effectively cleaning a fluid flow control system and more particularly to such a method utilized for cleaning automated painting equipment such as is required between applications of different colors of paint.
In spray painting of various types of products such as for example automobiles, automated machinery has been developed for supplying a variety of different types and colors of paint to the same application devices (i.e. spray guns). In many of these applications, successive automobiles or parts therefore are to be painted a different color. In order to accomplish this color change, it is necessary to quickly purge the paint supply lines leading to the applicators or spray guns so as to avoid intermixing of the different colors. Presently, this purging operation is accomplished by alternately pulsing set quantities of air and solvent through the supply lines. While this procedure is effective in cleaning of the system, it would be desirable to reduce the time required for this operation. Further, this cleaning operation requires a substantial amount of solvent be utilized which solvent usage is coming under increasingly greater scrutiny and regulation by various governmental agencies due to its potential harmful effect on the environment.
The present invention, however, provides a very effective method of cleaning such fluid supply systems in a significantly shorter time frame as well as greatly reducing the volume of solvent required to accomplish such a cleaning operation. According to the method of the present invention, solvent and air are intermixed via an adjustable ratio mixing valve which then supplies the mixed air and solvent to the supply system. The ratio mixing valve is preferably of the type disclosed and claimed in applicant's U.S. Pat. No. 4,924,900 entitled "Adjustable Ratio Mixing Valve" and is capable of maintaining a predetermined ratio between two separate fluid supplies irrespective of changes in the pressure at which the fluids are being supplied.
The method of the present invention offers substantial cost savings in terms of significantly reduced solvent usage while also greatly assisting users thereof in complying with the increasingly stricter solvent restrictions.
Additional advantages and features of the present invention will become apparent from the subsequent description and the appended claims taken in conjunction with the accompanying drawings.